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Objective To investigate the effects of banding width on hemodynamic characteristics of pulmonary artery (PA) by constructing pulmonary artery banding (PAB) models with different widths. Methods Based on clinical practice, with the same banding position and degree, computer-aided design (CAD) was utilized to reconstruct three-dimensional PAB models with different banding widths (2, 3, 4, 5 mm). Hemodynamic characteristics of the models with different banding widths, including pressure, streamlines, energy loss, energy efficiency and blood flow distribution ratio, were compared and analyzed through computational fluid dynamics (CFD). Results The pressure of PA decreased significantly, while the change of banding width had no significant effects on the pressure drop level at banding position. With the increase of banding width, the energy loss decreased, and the energy efficiency showed an upward trend. The blood flow of the left PA raised, and the ratio of blood flow distribution between the left PA and right PA increased, with the maximum reaching up to 2.28 : 1. Conclusions The increase of banding width can reduce the energy loss of PA and improve the energy efficiency of blood flow, but it will lead to the imbalance of blood flow distributions between the left and right lungs. Both the balance of blood flow distribution and the energy loss should be considered in choice for banding width of PAB. The virtual design of PAB surgery based on CAD and CFD will assist individualized banding width selection in future.
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Objective To optimize the design of three-dimensional (3D) printed scoliosis orthosis with computer-aided design (CAD), so as to achieve the advantages of good mechanical strength and lightweight model. Methods The body contour of a volunteer was scanned by a hand-held 3D scanner, then the body surface model of the volunteer was established. According to the three-point bending principles, traction and load-free principle, the body surface model was modified, and the pressure area and release area were designed. The model of scoliosis orthosis was then designed preliminarily. Comparative study on local optimization of hollow combinations with 32 different sizes were conducted using orthogonal experimental method. According to the optimization results, the model of scoliosis orthosis was hollowed out and biomechanically analyzed. The stress distributions of the 3D printed hollow scoliosis orthosis were compared, and its optimization effect was verified. Results By adopting the optimal design of local hollowing-out with 9 mm-radius and 23 mm-spacing circular hole (40% local weight loss), the 3D printed scoliosis orthosis with lighter weight, better air permeability and sufficient strength could be obtained. Conclusions Based on finite element biomechanical analysis, by adopting local hollow optimization design of circular hole at non-stress area, the 3D printed scoliosis orthosis can achieve the advantages of less printing materials and increased air permeability, and ultimately improve the wearing comfort and compliance of patients.
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Nowadays, digital dentistry is generally applied to prosthodontics with fabrication of inlays or any other fixed prostheses by utilizing CAD/CAM (computer-aided design/computer-aided manufacturing) technology and intraoral scanner. However, in fabricating removable prosthesis, there are some limitations for digital technology to substitute conventional casting method. Therefore, approaching removable prostheses fabrication with CAD/CAM technology would be a meaningful trial. In this case report, Kennedy class III mandibular edentulous patient who was in need of increasing the vertical dimension of occlusion was treated with removable partial denture using CAD and rapid prototyping technique. Surveying and designing the metal framework of the partial denture was performed with CAD, and sacrificial plastic pattern was fabricated with rapid prototyping technique. During the follow up period of nine months, the removable partial denture has provided satisfactory results in esthetics and function.
Subject(s)
Humans , Computer-Aided Design , Dentistry , Denture, Partial , Denture, Partial, Removable , Esthetics , Follow-Up Studies , Inlays , Methods , Plastics , Prostheses and Implants , Prosthodontics , Vertical DimensionABSTRACT
Objective:To explore the method of the establishment of edentulous mandible All-on-4 implant photoelastic model with various distally tilted implants by computer-aided design(CAD).Methods:The edentulous mandible specimen was scanned by CT. Three-dimensional models of the mandible consisting of implant location were reconstructed and edited with Mimics and Geomagic Stu-dio software.Each of the four models had four implant sockets in the interforaminal area.In the first model,the bilateral distal im-plants were placed vertically.In the other models,the posterior implants were respectively inclined by 1 5°,30°and 45°distally.The four models were manufactured by RP and then the All-on-4 photoelastic models were made by traditional ways.Results:The ob-tained ethoxyline resin models featured bright surface,homogeneous structure,faintly yellowish,high optical sensibility,precision im-plants location and with no natural stress.The model offered a good experimental basis for the stress measurement.Conclusion:The method of fabricating ethoxyline resin models by CAD is reproducible,which simplifies the operating process.
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Objective To measure the hip anatomic parameters and explore the differences between the hip fracture group and the normal group, analyze their effect on the incidence of hip fractures and fracture types by using computer aided design (CAD) and three-dimensional reconstruction technique. Methods Through CT scan images from the lower-extremity of hip fracture patient, the 3D anatomic model was established by Mimics10.01 software, and the 3D anatomic parameters of the normal proximal femur, namely femoral neck anteversion angle (FNAA), neck-shaft angle (NSA), femoral head diameter (FHD), length of femoral neck axis (LFNA) in the lower-extremity were measured. Results The averages of FNAA, NSA, FHD, LFNA in femoral neck fracture group were (7.9±4.6)°, (128.6±4.6)°, (46.0±4.6) mm, (47.1±5.1) mm, and those parameters in intertrochanteric fracture group were (15.5±6.8)°, (134.7±6.9)°, (45.3±3.6) mm, (46.7±3.4) mm. The FNAA and NSA in intertrochanteric fracture group were significantly larger than those in femoral neck fracture group regardless of gender (P<0.01). The FNAA and NSA in both fracture groups showed significant differences as compared with the normal group. ConclusionsThe risk of femoral intertrochanteric fracture will increase when the FNAA is larger than the normal range in Chinese, while the risk of femoral neck fracture will increase when the FNAA is smaller than the normal range in Chinese. The NSA of hip fracture patients was larger as compared with normal Chinese. The larger NSA will lead to a higher risk of femoral intertrochanteric fracture. There exist some differences in anatomic parameters of the proximal femur between the fracture group and the normal group, especially in the angle parameter. The femoral intertrochanteric fractures are more prone to occur in the older people, while the femoral neck fractures are more prone to occur in the younger people.
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Objective To explore a method of large cranial bone defect reconstructed by titanium implant with computer aided design(CAD)/computer aided manufacture(CAM)technique.Methods From April 2006 to June 2008,7 cases of cranial bone defect due to tumor and trauma were admitted.The data of skull bone defects were obtained by CT.The resin model was designed and manufactured with rapid prototyping technique.Results The CT data could be used by image software directly.The resin model was manufactured accurately by RP technique.The titanium implant design could be completed by CAD/CAM.7 patients achieved one stage healing.After a follow-up of 6 months to 1 year,cranial bone defect was reconstructed satisfactorily.Conclusion Individual design and repair of large cranial bone defect with CAD/CAM technique is worth extending application clinically.It is a quite ideal and very simple method for the surgical treatment of the cranial bone defect.
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Objective:To investigate the feasibility of 3-D computer aided design(CAD)for the framework of a mandibular Kennedy Class Ⅱ,Modification 2 arch.Methods:In terms of the principle of clinical design,the 3-D framework was built with the technique of mixed model of points cloud,curves and surfaces on the reconstructed model of a partially edentulous cast,including the tissue surfaces and polishing surfaces of every component,such as clasp,rest,lingual bar and mesh construction,etc.Results:Preliminarily,a CAD method for 3-D RPD framework design was established and a individualized RPD framework 3D geometric model was set up.Conclusion:CAD for RPD framework design based on the mixed model of points cloud,curves and surfaces is feasible.